Abstract: [Object] To provide an optical device for use with coherent terahertz light, which enables to reduce and remove an unwanted interference pattern, and to acquire a terahertz image of high image quality. [Solving Means] The optical device for use with coherent terahertz light includes an optical system (2) that uses coherent terahertz light beam (1) whose frequency(ies) is/are within a range from 0.1 to 10 THz. A structure(s) (4) being located outside of effective diameter (3) of the beam (1) and including anti-reflection material (5) on an area(s) of the structure, the area(s) is/are facing to the beam (1).

Abstract: The invention provides a semiconductor optical modulator including a two-step mesa optical waveguide having a first clad layer (101); a mesa-like core layer (102) formed over the first clad layer (101); and a second clad layer (103) formed into a mesa shape over the core layer (102), and having a mesa width smaller than that of the core layer (102). The two-step mesa optical waveguide includes a multi-mode optical waveguide region to which an electric field is applied or into which an electric current is injected, and a single-mode optical waveguide region to which the electric field is not applied and into which the electric current is not injected. When the mesa width of the core layer in the multi-mode optical waveguide region is defined as Wmesa1, and the mesa width of the core layer in the single-mode optical waveguide region is defined as Wmesa2, Wmesa1>Wmesa2 is satisfied.

Abstract: Provided is a semiconductor device with a high breakdown voltage yield of a bipolar transistor and a high bandwidth and quantum efficiency of a light receiving element. An optical semiconductor device includes monolithically integrated transistor and light receiving element. The light receiving element includes a p-type semiconductor layer, an n-type epitaxial layer formed on the p-type semiconductor layer, and an n-type diffusion layer formed on the n-type epitaxial layer. An n-type impurity concentration of the n-type diffusion layer is 3×1018 cm?3 or less at a depth of 0.12 ?m or more below a surface of the n-type diffusion layer, 1×1016 cm?3 or more at a depth of 0.4 ?m or less below the surface, and 1×1016 cm?3 or less at a depth of 0.8 ?m or more below the surface, and an interface between the p-type semiconductor layer and the n-type epitaxial layer is located at a depth of 0.9 ?m to 1.5 ?m below the surface.

Abstract: The invention provides a semiconductor optical modulator including a two-step mesa optical waveguide having a first clad layer (101); a mesa-like core layer (102) formed over the first clad layer (101); and a second clad layer (103) formed into a mesa shape over the core layer (102), and having a mesa width smaller than that of the core layer (102). The two-step mesa optical waveguide includes a multi-mode optical waveguide region to which an electric field is applied or into which an electric current is injected, and a single-mode optical waveguide region to which the electric field is not applied and into which the electric current is not injected. When the mesa width of the core layer in the multi-mode optical waveguide region is defined as Wmesa1, and the mesa width of the core layer in the single-mode optical waveguide region is defined as Wmesa2, Wmesa1>Wmesa2 is satisfied.

Abstract: The present invention intends to improve communication efficiency between two communication apparatuses each engaged in the communication by full duplex communication method by using a surplus band of the one to transmission band of the other. A first bandwidth required by a first communication apparatus (A) at data transmission and a second bandwidth required by a second communication apparatus (B) at data transmission are presumed. Next, the first bandwidth presumed as mentioned is compared to a first bandwidth used which the first communication apparatus (A) currently uses and at the same time, the second bandwidth presumed as mentioned is compared to a second bandwidth used which the second communication apparatus (B) currently uses. The first bandwidth and the second bandwidth are then adjusted, and a third bandwidth which the first communication apparatus (A) uses at data transmission and a fourth bandwidth which the second communication apparatus (B) uses are determined.

Abstract: Provided is a semiconductor device with a high breakdown voltage yield of a bipolar transistor and a high bandwidth and quantum efficiency of a light receiving element. An optical semiconductor device includes monolithically integrated transistor and light receiving element. The light receiving element includes a p-type semiconductor layer, an n-type epitaxial layer formed on the p-type semiconductor layer, and an n-type diffusion layer formed on the n-type epitaxial layer. An n-type impurity concentration of the n-type diffusion layer is 3×1018 cm?3 or less at a depth of 0.12 ?m or more below a surface of the n-type diffusion layer, 1×1016 cm?3 or more at a depth of 0.4 ?m or less below the surface, and 1×1016 cm?3 or less at a depth of 0.8 ?m or more below the surface, and an interface between the p-type semiconductor layer and the n-type epitaxial layer is located at a depth of 0.9 ?m to 1.5 ?m below the surface.

Abstract: A balun circuit includes a first CPW line 11, a second CPW line 12a, and a third CPW line 12b that serve as signal input/output ports; a first CPS line 14a that is a differential transmission line, the first CPS line 14a relaying the first CPW line 11 to the second CPW line 12a; a second CPS line 14b that is a differential transmission line, the second CPS line 14b relaying the first CPW line 11 to the third CPW line 12b; and at least one connection section that connects grounded conductors of each of the first CPW line 11, the second CPW line 12a, and the third CPW line 12b.

Abstract: Problem: A storage medium playback device includes a first playback means that plays back on the basis of information stored on a storage medium, a second playback means that plays back on the basis of information stored on a storage medium, and a single insertion slot through which a storage medium to be played back by the first playback means and a storage medium to be played back by the second playback means are inserted, wherein the storage playback device is capable of simultaneously playing back different storage media each with the first playback means and the second playback means; therefore, the area of an installation face for insertion slots is effectively used.

Abstract: The present invention intends to improve communication efficiency between two communication apparatuses each engaged in the communication by full duplex communication method by using a surplus band of the one to transmission band of the other. A first bandwidth required by a first communication apparatus (A) at data transmission and a second bandwidth required by a second communication apparatus (B) at data transmission are presumed. Next, the first bandwidth presumed as mentioned is compared to a first bandwidth used which the first communication apparatus (A) currently uses and at the same time, the second bandwidth presumed as mentioned is compared to a second bandwidth used which the second communication apparatus (B) currently uses. The first bandwidth and the second bandwidth are then adjusted, and a third bandwidth which the first communication apparatus (A) uses at data transmission and a fourth bandwidth which the second communication apparatus (B) uses are determined.

Abstract: A balun circuit includes a first CPW line 11, a second CPW line 12a, and a third CPW line 12b that serve as signal input/output ports; a first CPS line 14a that is a differential transmission line, the first CPS line 14a relaying the first CPW line 11 to the second CPW line 12a; a second CPS line 14b that is a differential transmission line, the second CPS line 14b relaying the first CPW line 11 to the third CPW line 12b; and at least one connection section that connects grounded conductors of each of the first CPW line 11, the second CPW line 12a, and the third CPW line 12b.

Abstract: A supplementary roller is disposed on the end of a disk guiding section 71 so that the outer face 72c of the cylindrical shaped section 72b of the supplementary roller is placed on the conveying roller 73 side by the protruding section 71a formed on disk guiding section 71.

Abstract: A disk device is provided with an MD carrying mechanism which uptakes an MD 24, places the MD 24 on a turntable, and performs the ejection of the MD 24 from the turntable by the displacement of the holder drawing lever 39 which forms part of a linking mechanism when the cartridge of the MD 24 is inserted into an MD holder. The disk device also comprises a clamp lever avoidance mechanism which refuges the clamp lever 17, which is used for clamping the CD 200, to a position which does not interfere with the uptake and ejection of the MD during uptake and ejection of the MD by the MD carrying mechanism.

Abstract: A disk device is comprised of a CD conveying mechanism which performs the uptake and ejection of CDs by a conveying roller 11. An MD conveying mechanism drives a clamp lever rotating mechanism which performs the refuge of the clamp lever 17 from an initial position and the return of the clamp lever 17 to an initial position by being driven by a CD loading drive motor. A CD is clamped by a clamp mechanism when the CD is loaded onto a fixed position in the device and directed to a turntable. When an MD 24 is loaded or ejected, the MD conveying mechanism drives the refuge or return of the clamp lever 17. The placement of an MD 24 on a turntable is performed by an MD placing mechanism which is driven as a result of an MD 24 being taken up to a fixed position in the device.

Abstract: In exposing a diffraction grating pattern on a resist, the diffraction grating pattern is exposed via EB on an active region and the adjacent thereto only and the region which is not exposed via EB is exposed via Deep UV light so that the resist may be left on the active region and the adjacent thereto only after the exposed resist is developed according to the process of forming a diffraction grating for a distributed feedback semiconductor laser of the present invention. In addition, the resist-coated area can be gradually reduced from the resist existing area to the non-resist existing area and the average height of the substrate on which said diffraction grating is formed can be gradually changed on the diffraction grating forming region and non-diffraction grating forming region which results in preventing the crystallinity of a semiconductor layer on the substrate from being deteriorated.

Abstract: A disk device comprises first and second disk selection projections 102, 103 which regulate an angle of the disk conveyed to a small or large disk positioning recess 121, 122 on the basis of an outer radius of the disk. The first and second disk selection projections have tapered faces 102a, 103a provided at fixed intervals on a disk guiding face 101a facing the conveying roller 111. The disk device further comprises steps 121a, 122a for positioning the small disk 201 or the large disk 200 having an angle regulated in accordance with the outer radius to the small disk positioning recess 121 or to the large disk positioning recess 122.

Abstract: A disk device is comprised of a feed roller displacement mechanism which displaces a position of a feed roller 11 to a position lower than a position when a CD 200 is inserted. When a CD 200 is ejected from the turntable, the position of the feed roller 11 displaced downwardly is returned to an initial insertion position.

Abstract: A disk holding device supports a disk as a recording medium.

Abstract: The present invention is provided with a reinforcing base section 5 which is secured to and engages with an independent lateral plate 2, 2 which is formed on a corner section of a chassis 1 and a damper 6 which is integrated with said reinforcing base section 5 and which absorbs vibrations of said disk playing unit. In this way, it is possible to reinforce in a simple way a corner section of a chassis 1 which is formed by progressive die molding. In addition, since the damper section 6 is disposed simultaneously by the fixation of the reinforcing base section 5 to the chassis 1, it is possible to improve the efficiency of the assembly operation at each stage, reduce the number of components and reduce costs.

Abstract: A supplementary roller is disposed on the end of a disk guiding section 71 so that the outer face 72c of the cylindrical shaped section 72b of the supplementary roller is placed on the conveying roller 73 side by the protruding section 71a formed on disk guiding section 71.

Abstract: The bearing device comprises a bearing 4, a washer 5 and a coupling piece 6 that couples the bearing 4 to the washer 5 and/or separates itself from the washer 5 and the bearing 4 by a pressure force applied thereto, wherein the bearing, the washer and the coupling piece are integrally formed with each other, and the base flap 7 is formed with a projection 7b. Due to this construction, an operator can easily hold the bearing 4 and the washer 5 as one component, and as the coupling piece 6 can be readily removed by the projection 7b, a working efficiency for installing this device can be drastically improved, and the automated mounting operation thereof can also be easily implemented.